src/picture/templatetags/picture_tags.py

   1 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   2 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   3 #
   4 import logging
   5 from random import randint
   6 from django import template
   7 from django.urls import reverse
   8 from django.utils.cache import add_never_cache_headers
   9 import sorl.thumbnail.default
  10 from ssify import ssi_variable
  11 from catalogue.utils import split_tags
  12 from ..engine import CustomCroppingEngine
  13 from ..models import Picture
  14
  15
  16 register = template.Library()
  17
  18 cropper = CustomCroppingEngine()
  19
  20
  21 @register.inclusion_tag('picture/picture_wide.html', takes_context=True)
  22 def picture_wide(context, picture):
  23     context.update({
  24         'picture': picture,
  25         'main_link': reverse('picture_viewer', args=[picture.slug]),
  26         'request': context.get('request'),
  27         'tags': split_tags(picture.tags),
  28         })
  29     return context
  30
  31
  32 @register.simple_tag()
  33 def area_thumbnail_url(area, geometry):
  34     def to_square(coords):
  35         w = coords[1][0] - coords[0][0]
  36         h = coords[1][1] - coords[0][1]
  37         if w == h:
  38             return coords
  39         elif w > h:
  40             return [[coords[0][0] + w/2 - h/2, coords[0][1]],
  41                     [coords[1][0] - w/2 + h/2, coords[1][1]]]
  42         else:
  43             return [[coords[0][0], coords[0][1] + h/2 - w/2],
  44                     [coords[1][0], coords[1][1] - h/2 + w/2, ]]
  45
  46     # so much for sorl extensibility.
  47     # what to do about this?
  48     _engine = sorl.thumbnail.default.engine
  49     sorl.thumbnail.default.engine = cropper
  50     coords = to_square(area.area)
  51
  52     try:
  53         th = sorl.thumbnail.default.backend.get_thumbnail(
  54             area.picture.image_file,
  55             geometry,
  56             crop="%dpx %dpx %dpx %dpx" % tuple(map(lambda d: max(0, d), tuple(coords[0] + coords[1]))))
  57     except ZeroDivisionError:
  58         return ''
  59     except Exception as e:
  60         logging.exception("Error creating a thumbnail for PictureArea")
  61         return ''
  62
  63     sorl.thumbnail.default.engine = _engine
  64
  65     return th.url
  66
  67
  68 @ssi_variable(register, patch_response=[add_never_cache_headers])
  69 def picture_random_picture(request, exclude_ids, unless=None):
  70     if unless:
  71         return None
  72     queryset = Picture.objects.exclude(pk__in=exclude_ids).exclude(image_file='')
  73     count = queryset.count()
  74     if count:
  75         return queryset[randint(0, count - 1)].pk
  76     else:
  77         return None